Heart failure (HF) accounts for 1 in 4 deaths in the US each year, making it the leading cause of death with a HF patient population of over 6.5 million people. Due to a scarcity of donor hearts, left ventricular assist devices (LVADs) have gained clinical acceptance as an alternative treatment option to heart transplantation due to their durability and long-term viability. Improved survival and reduced mortality have been associated with less invasive and off-pump approaches. Current clinically-approved LVADs require aortic partial clamping to facilitate outflow graft anastomosis and may also require cross-clamping of the aorta and cardiopulmonary bypass (CPB) during LVAD implantation. To improve clinical outcomes, MAST LLC (Louisville, KY) is developing a two-balloon partial occlusion device (CardiAction) designed to provide a safe, reliable, and effective hemostatic field that allows for the anastomosis of an LVAD outflow graft without the need for external clamping. The CardiAction system internally occludes the ascending aorta (clamping), creating a hemostatic pocket for which an anastomosis can be placed, while still allowing vessel perfusion (up to 5 L/min flow, < 5 mmHg) without vessel tissue damage. CardiAction is a catheter-based system comprised of a balloon-stent structure, multi-lumen conduit, and a delivery sheath. The balloon-stent structure, which consists of two polyurethane, toroidal balloons positioned on the ends of a woven-polyester covered self-expanding and collapsible stent, will provide aortic occlusion enabling the perfusion through the device lumen. The balloons are inflated until sufficient vessel wall contact is achieved, creating a static environment between the balloons. The multi-lumen conduit and delivery sheath will assist in device placement, deployment, and retraction. The proposed tool will be a less invasive 18Fr sheath catheter-based solution. The stent cover provides a central lumen for perfusion, eliminating risks associated with complete vessel occlusion. The inflated balloons provide intravascular occlusion that maintains the natural vascular structure, thereby creating a static environment that will provide the surgeon with a leak-free area to operate on the vessel while also reducing the potential for tissue damage. In this SBIR phase I proposal, we will demonstrate feasibility of the CardiAction system, and then plan to submit a phase II proposal to complete engineering development to achieve a design freeze of the CardiAction system and complete pre-clinical testing to demonstrate efficacy, safety, and reliability. The phase II experimental data will be used to support an Investigational Device Exemption (IDE) application to the Food and Drug Administration (FDA) for clinical trials.